The fatal smoke calamity in a Metro tunnel Jan. 12 was exacerbated by the transit agency’s slow response to the crisis, including a critical communications breakdown and poor coordination among subway workers as they tried to help scores of riders trapped in a train filled with noxious fumes, according to documents made public Tuesday.

As the National Transportation Safety Board began two days of fact-gathering public hearings, investigators questioned Metro engineers, first responders and other specialists about technical aspects of the incident, including subway electrical systems, ventilation fans and air shafts.

But the most dramatic new information to emerge were first-person accounts of the crisis from transcripts of interviews with transit workers involved in the incident, which killed one rider on a Yellow Line train and sickened at least 86 others.

In an interview with investigators, the operator of the train that stopped in the smoke-filled tunnel that day, just south of L’Enfant Plaza, described harrowing chaos. As he pleaded with central train controllers for permission to back out of the tunnel, he said, he was repeatedly told to “Stand by. Stand by” while screaming passengers desperate to escape were “kicking and banging” on the doors.

“I was going back and forth with them, saying, ‘Central: Be advised — I got people on the train. They’re saying they can’t breathe, they’re coughing, they’re vomiting. I need to get back to the platform,’ ” James Curley said in his debriefing.

But despite the smoke in the tunnel, additional train traffic in the vicinity of the L’Enfant Plaza station was not stopped, according to interview transcripts the safety board made public Tuesday.

A train controller at Metro’s Rail Operations Control Center (ROCC) in Landover told investigators that she tried to halt a train behind Curley’s train, but the operator of the second train said she did not hear any such message.

As a result, while Curley was asking the ROCC for clearance to return southbound Yellow Line train No. 302 to L’Enfant Plaza, the train right behind him already had pulled into the L’Enfant station, taking up most of the platform space.

And because smoke from the tunnel had begun pouring into the station, the operator and passengers of the second train, No. 510, were evacuated by Metro Transit Police officers, leaving the southbound side of the station largely occupied by an empty train. ROCC employees, thinking that the operator of train No. 510 was still on board, tried to arrange for the train to be moved out of the station, but their efforts were in vain.

The transcripts of the interviews with both train operators and other Metro workers are the first direct accounts from transit employees to be disclosed since the Jan. 12 calamity.

As the first of two days of hearings began, Metro officials and others who answered safety investigators’ questions were instructed to stick to the facts and avoid offering their opinions or analysis. The NTSB has said its final report on the incident will be issued early next year.

The roughly 6,000 pages of documents made public portray a state of confusion at the Landover control center, where “everyone was literally in a frenzy,” one ROCC employee said. And they reveal a failure of communications among the ROCC, the two trains and Metro Transit Police officers in the L’Enfant Plaza station.

Curley, seeking authorization to back out of the tunnel, said the ROCC kept telling him that it was “trying to clear the tracks” in the L’Enfant Plaza station. But Transit Police officers in the station would not allow train No. 510 to be moved out of the way. A Metro operations supervisor told investigators that he boarded the empty train, intending to move it, but that “the officers . . . literally took me off the train.”

Meanwhile, in the tunnel, Curley “was trying to advise the customers to be calm, trying to get them back to platform as soon as I could,” he said. “They’re scared, they’re yelling. . . . To be truthfully honest, it was so dark, and pretty much the smoke was everywhere. I saw many people laying on the train floor. . . . At that point, I knew they were on the floor because they were trying to not inhale all the smoke.”

The lead car of Curley’s train was 836 feet into the tunnel when it ran into the heavy smoke, caused by what the NTSB has said was a meltdown of track-based electrical equipment. “I couldn’t see anything,” Curley said. “The smoke was . . . incredibly thick.”

The electrical malfunction that produced the smoke occurred 1,100 feet ahead of the lead car, according to investigators.

Curley said: “As soon as I saw it,” about 3:15 p.m., “I immediately stopped the train” and notified the ROCC, telling train controllers, “Heavy smoke, zero visibility, need to reverse ends and try to make my way back to the platform.

“. . . I kept repeating myself over and over and over with Central. . . . They are saying: ‘Stand by. Stand by. Stand by. We’re trying to get the platform clear.’ ”

But it never happened. Curley’s train stayed put in the tunnel, with smoke filling its six cars, while about 380 gasping passengers — some barely conscious — waited more than 30 minutes for rescuers to arrive and start an evacuation. An autopsy found that the deceased rider, Carol I. Glover, 61, a grandmother from Alexandria, suffered respiratory failure due to smoke exposure.

Curley said he had begun his southbound Yellow Line run, headed to Virginia, at the Fort Totten station. “My day was fine,” he told investigators. “I didn’t have no problems.”

Then, moments after leaving L’Enfant Plaza, he said, “I went around and bent the corner. The next thing you know, the smoke was just — it was real thick, real heavy.”

Metro trains have operator booths at both ends. After Curley stopped and notified the ROCC about the smoke, he said, “they gave me permission to key out, reverse ends,” meaning to go to the rear booth and prepare to drive the train back to L’Enfant Plaza.

The cars were rapidly filling with fumes, he said: “There was plenty of people who were saying that they are on the floor, that they couldn’t breathe and they felt like they were about to pass out.” He said he told the passengers: “I understand. I’m in this with you. I’m trying to get everybody back to the platform. Just please stay calm.”

On the other side of L’Enfant Plaza, meanwhile, southbound train No. 510 was approaching the station. The operator, Connie Conner, told investigators that she heard Curley on the radio from train No. 302 asking the ROCC for clearance to return to L’Enfant. Conner said she did not stop her train outside the station, in order to leave room at the platform for Curley’s train, because the control center did not instruct her to do so.

In a separate debriefing, however, ROCC controller Vale’re White contradicted Conner, saying that she did give that order. “I go, to 510: ‘510, stop your train.’ I said it to her twice.”

Conner proceeded into the station. “Next thing I know, I’m engulfed in smoke,” she told investigators. The fumes were so thick, she said, she could see only a short distance in front of her. She opened a train window and asked a Transit Police officer in the station to guide her, which he did, using a flashlight and keeping one hand on the lead car.

When train No. 510 eased to a stop, the NTSB said, 100 feet of space was between the front car and the end of the platform. The officer then ordered Conner and her passengers to evacuate, saying, “We need to get these people out of here now.”

After leaving the station, Conner said, she saw Adams, the rail supervisor. Adams told investigators that he asked Conner whether she was the operator of train No. 510. “And she said, ‘Yes.’ So I said, ‘Okay, they want us to try to move the train off the platform.’ So I run ahead of her, down to the platform.”

Adams continued: “It was just so much smoke in the station, I couldn’t see anything. . . . At some point, I actually got on the train. . . . In my mind, I’m trying to do everything I can to try to move that train, to help the control center.” But within moments, Adams said, Transit Police officers were “pulling me off.”

Listening to radio chatter, Adams said, he heard ROCC workers trying to reach the operator of train No. 510. One of the controllers, Fannie Smith, later said in a debriefing: “Just to find out that we wasted all that time talking to an empty train — it was just frustrating. I was, like, ‘Unbelievable.’ ”

So train No. 510 stayed put, occupying all but the last 100 feet of platform space before the entrance to the smoke-filled tunnel in which train No. 302 was immobile.

As for Curley, he said that when he reached the rear booth of train No. 302, an ROCC employee told him to turn off the train’s air-intake system, which had been pulling fumes into the cars. The NTSB has said that the intake system remained on while the train was in the tunnel. But Curley said in his debriefing that the system stayed activated while he walked from the front car to the operator’s booth at the rear. Then he shut it down.

As for returning to the station, an ROCC employee “said something to me about Transit [Police] was not letting them remove the train that was on the platform at L’Enfant Plaza,” Curley recalled. “So then I came on the air, and I said: ‘Well, Central, I have two Transit cops on board. They need to get in contact with the Transit cops on the platform so they can move the train.’ ”

Curley said he sought help from the two officers, both women.

“I got on the intercom, and I spoke to the Transit cops on the train, saying: ‘Central is telling me that the Transit officers” at L’Enfant are “not trying to remove the train from off the platform. Can you all get in contact with them?’ ” But the officers on Curley’s train were busy with frantic riders. “They were Transit cops, but they were still two small females dealing with a packed train, so they was getting bombarded with the people.”

In Landover, controllers had been trying to contact train No. 510 in the L’Enfant station “to no avail,” unaware that the operator was no longer aboard, said Marcel Malloy, an assistant ROCC superintendent. A computer console at the control center showed that the train was in the station, but the computer system cannot pinpoint a train’s exact position along a platform, according to several statements made to investigators.

At the same time, a video image from a security camera at the L’Enfant Plaza station that appeared on a screen at the ROCC did not show controllers that there were 100 feet of open space between the front of train No. 510 and the mouth of the tunnel.

“All you could see was smoke,” Malloy said in his debriefing. Had controllers known about the free space, he said, they would have cleared train No. 302 to return to the station because there was “absolutely” enough room for one of its six cars to fit along the platform. The passengers could have then evacuated through that car.

For several minutes, while Curley kept asking for permission to back up to the station and while train controllers tried to clear space along the L’Enfant platform, there had been a window of opportunity for train No. 302 to escape the smoke.

But the window abruptly closed, Curley said, because his train suddenly lost propulsion power. At that point, he and his passengers could only wait for rescuers to arrive.

About 30 minutes after Curley first saw the smoke, D.C. firefighters reached his train and began escorting the shaken, ailing riders to safety.

“I carried a couple of people from the train up to the platform,” Curley told investigators. He said he also alerted firefighters “that there was a wheelchair person on my train. . . . I wanted to make sure that the wheelchair guy had gotten off.” Then: “I went to the platform. . . . I was pretty much trying to catch my breath.”

In the station, he saw a rail supervisor. “I can’t remember what his name was,” Curley said. “He walked me from the platform to upstairs, outside to get some air.